I never doubted the wisdom of the Mac Pro. Recall that print is my main biz so I plan to repurpose the iMac and use as Bay 2 for some video and mostly print & photo editing, and then buy the MP when it has 'all that jazz' this fall.
Sounds like you'll have a nice suite!
I think you'll be in good shape with the iMac for a while. Did you say you use After Effects, as well?